What is the ‘Kraken' Variant? What We Know About the New COVID Variant So Far

You may have heard about a so-called "kraken" variant circulating right now, but what exactly is it and why is being called that?

The nickname refers to the XBB.1.5 variant, which has quickly become the dominant COVID strain in the U.S.

But why the "kraken" variant?

Dr. Ryan Gregory, a biology professor at the University of Guelph in Ontario, Canada, said the nickname was simply "intended to help people keep track of who's who in the ever-growing variant soup."

In a tweet earlier this week, Gregory stressed the nickname was "informal." Previous variants have also been given nicknames like the "nightmare" or "scrabble" variants.

Regardless of which name you've seen, the now-dominant COVID variant has been making headlines for a variety of reasons in the new year.

Here's a look at what we know so far and what experts are saying:

What Is XBB.1.5?

The variant is XBB.1.5, a highly contagious "recombinant" variant that spawned from two different BA.2 variants. It is related to the XBB variant, which was previously behind a COVID surge in Singapore.

"It's basically just a combination of two of the earlier subtypes, two variants," said Chicago Department of Public Health Commissioner Dr. Allison Arwady Tuesday.

What is Different About XBB.1.5?

The variant has quickly rose to dominance, as experts say it is more contagious than many of its predecessors.

"It went from 4% of sequences to 40% in just a few weeks," Dr. Ashish Jha, White House COVID czar, tweeted. "That’s a stunning increase."

Jha said the variant is likely more immune evasive, even "more than other omicron variants."

Arwady also said the variant is "clearly more infectious" than other variants, "meaning it's spreading more easily" and "outcompeting the other variants."

Andrew Pekosz, a virologist at Johns Hopkins University, told CNBC the XBB.1.5 has an additional mutation that makes it bind better to cells.

"The virus needs to bind tightly to cells to be more efficient at getting in and that could help the virus be a little bit more efficient at infecting people," Pekosz said.

Jha echoed that finding, saying the variant "binds more tightly to the human ACE receptor," which can affect contagiousness.

Where is XBB.1.5 Highest Right Now?

Within the last two months, tracking numbers from the Centers for Disease Control and Prevention showed the XBB.1.5 variant has climbed to now make up more than 40% of cases in the U.S. In the Midwest, however, the numbers are much lower, with XBB.1.5 making up just 6% of cases.

Currently, the new variant is surging largely in the Northeast, where it makes up more than 75% of cases.

Is XBB.1.5 Making People Sicker?

The rapid rise in dominance has led some experts to question whether or not the variant will lead to added concerns in the weeks following holiday gatherings, with COVID hospitalizations already rising in the U.S.

While it's not clear where the variant originated exactly, Arwady said it has so far not shown signs of leading to more severe infections.

"They are seeing some increase in hospitalizations in older folks in the Northeast, but that seems to be at least based on what you know, I'm reading and hearing from folks, that seems to be based as much on the fact that they're seeing just a surge overall... and so with that increase, it seems like we're just seeing more older people get infected and if they're not up-to-date, especially with their vaccines, they are somewhat more likely to be hospitalized," she said during a Facebook Live Tuesday. "But no, I haven't seen anything suggesting that this new subvariant is clearly making people sicker. I think we'll learn more as we follow it."

COVID-19 hospitalizations are rising in the United States, even as hospitalizations for respiratory syncytial virus and the flu continue to fall.

One concern is that recent strains of COVID have left some treatment options ineffective.

"As this virus continues to mutate, what we have seen is that all of what are called our monoclonal antibodies, our clinical monoclonal antibodies are inactive against these most recent subvariants," Arwady said. "And the monoclonal antibodies are these IV infusions that people with really severe immunocompromised will often take people who have a organ transplant, for example, and the vaccine doesn't work very well because their whole immune system has been tamped down and even though they take the vaccine, it's safe, they don't mount enough of an immune response, and so we've historically used what's called a monoclonal antibody, which helps give them passive protection, but the problem is that as these new subvariants have gotten further and further from the original...the virus has figured out how to mutate around them. So we have lost most of that monoclonal antibody treatment."

Arwady noted that while there are significant concerns surrounding the new strain, it remains an omicron subvariant, which offers less risk than if the variant were in an entirely different family.

"It's in that variant of interest category. We label it, we monitor it, we give it those those alphabet soup of letters to be able to keep track of it, but the big worry is if we see something emerge and grow to be a new variant of concern, meaning it gets a new letter in the Greek alphabet," Arwady said. "We haven't had one of those in a year. I hope we never have one again."

Do Boosters Work on XBB.1.5?

Experts have said the bivalent COVID booster appears to offer some protection against the newer strains, particularly against severe illness, in large part because they remain under the omicron family.

"It does look like the vaccine, the bivalent booster is providing continued protection against hospitalization with these variants," Pekosz told CNBC. "It really emphasizes the need to get a booster particularly into vulnerable populations to provide continued protection from severe disease with these new variants."

But Jha noted that for those who had infections before July or who haven't received a bivalent COVID booster shot, protection is much lower.

"Right now, for folks without a very recent infection or a bivalent vaccine, you likely have very little protection against infection," he tweeted.

What Are the Symptoms Associated With the Variant?

Arwady said COVID symptoms haven't changed with the new variant, though she noted that symptoms similar to the flu are less common, particularly in those who are vaccinated and boosted.

"COVID is showing up very much like it already has. I think, if anything, we are seeing it a little bit less likely to have the more severe symptoms," Arwady said. "Definitely people get the severe symptoms still, especially if they're not up-to-date with their vaccines. But more often now we are seeing people - especially if they're fully up-to-date, maybe it's their second time getting COVID, whatever it might be - we're seeing more people actually just have cold-like symptoms, less likely to have those flu-like, really feeling very sick, the high fevers."

Will There Be Another Surge Associated With the New Variant?

The answer here is unclear.

Experts say they are monitoring as the variant quickly climbs in numbers.

"Whether we’ll have an XBB.1.5 wave (and if yes, how big) will depend on many factors Including immunity of the population, people’s actions, etc.," Jha said.

Arwady said Chicago was closely monitoring what happens in the Northeast, which has previously seen surges ahead of the Midwest. She added that hospitalizations have not risen to levels seen earlier in the pandemic.

"Am I concerned about XBB.1.5? Yes," Jha said. "Am I worried this represents some huge set back? No."